HttpPost工具类

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;

import android.content.Context;
/**
 * 向服务器端发送POST数据
 * @author LinHang_He
 *
 */
public class PostUtils {
	private String path;
	private Context context=null;
	
	public PostUtils(String path)
	{
		this.path=path;
	}
	/**
	 * 构造函数
	 * @param path 请求URL地址
	 * @param context 当前上下文对象
	 */
	public PostUtils(String path,Context context)
	{
		this.path=path;
		this.context=context;
	}
	/**
	 * 发送POST请求
	 * @param str 向服务器端发送的数据
	 * @return
	 */
	public String setPostRequest(String str){
		try {
			byte [] entity=str.getBytes();
			HttpURLConnection conn=(HttpURLConnection)new URL(path).openConnection();
			conn.setConnectTimeout(5000);
			conn.setRequestMethod("POST");
			conn.setDoOutput(true);
			conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
			conn.setRequestProperty("Content-Length",String.valueOf(entity.length));
			OutputStream outStream=conn.getOutputStream();
			outStream.write(entity);
			InputStream is=conn.getInputStream();
			
			if(conn.getResponseCode()==200)
			{
				return inputStreamToString(is,"utf-8");
			}
			else{
				System.out.println("error");
				return "timeout";
			}
		} catch (MalformedURLException e) {
			
			// TODO Auto-generated catch block
			e.printStackTrace();
			return "timeout";
		} catch (ProtocolException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			
			return "timeout";
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			
			return "timeout";
		}
		
	}	
	
	/**
	 * 将字符流转换成字符串
	 * @param is 输入数据流
	 * @param encoding 字符编码
	 * @return
	 */
	private String inputStreamToString(InputStream is, String encoding) {
	    try {
	        // byte[] b = new byte[1024];
	    	byte[] b = new byte[1];
	         String res = "";
	         if (is == null) {
	                return "";
	         }
	         
	         int bytesRead = 0;
	         while (true) {
	        	 
	             bytesRead = is.read(b, 0, 1); // return final read bytes counts
	             if (bytesRead == -1) {// end of InputStream
	                    return res;
	             }
	             res += new String(b, 0, bytesRead, encoding); // convert to string using bytes
	          }
	      } catch (Exception e) {
	            e.printStackTrace();
	            System.out.print("Exception: " + e);
	            return "";
	      }
	}

}